78 research outputs found
Soil-Pile Interaction in Vertical Vibration
This paper deals with the theoretical study concerning soil-pile interaction in vertical vibration for both the floating pile and the pile group. The analysis is made by applying the elastic wave theory to the viscoelastic layer overlying on the rigid bedrock. Further, the displacement responses of the pile and the complex stiffness at the pile head subjected to the harmonic excitation at the top of the pile are obtained for various parameters
The control of reproductive physiology and behavior by gonadotropin-inhibitory hormone
Gonadotropin-releasing hormone (GnRH) controls the reproductive physiology and behavior of vertebrates by stimulating synthesis and release of gonadotropin from the pituitary gland. In 2000, another hypothalamic neuropeptide, gonadotropin-inhibitory hormone (GnIH), was discovered in quail and found to be an inhibiting factor for gonadotropin release. GnIH homologs are present in the brains of vertebrates, including birds, mammals, amphibians, and fish. These peptides, categorized as RF amide-related peptides (RFRPs), possess a characteristic LPXRF-amide (X = L or Q) motif at their C-termini. GnIH/RFRP precursor mRNA encodes a polypeptide that is possibly cleaved into three mature peptides in birds and two in mammals. The names of these peptides are GnIH, GnIH-related peptide-1 (GnIH-RP-1) and GnIH-RP-2 in birds, and RFRP-1 and RFRP-3 in mammals. GnIH/RFRP is synthesized in neurons of the paraventricular nucleus of the hypothalamus in birds and the dorsomedial hypothalamic area in mammals. GnIH neurons project to the median eminence, thus providing a functional neuroanatomical infrastructure to regulate anterior pituitary function. In quail, GnIH inhibits gonadal activity by decreasing synthesis and release of gonadotropin. The widespread distribution of GnIH/RFRP immunoreactive fibers in all animals tested suggests various actions within the brain. In accordance, GnIH/RFRP receptor mRNA is also expressed widely in the brain and the pituitary. GnIH/RFRP immunoreactive axon terminals are in probable contact with GnRH neurons in birds and mammals, and we recently demonstrated expression of GnIH receptor mRNA in GnRH-I and GnRH-II neurons in European starlings. Thus, GnIH/RFRP may also inhibit gonadotropin synthesis and release by inhibiting GnRH neurons in addition to having direct actions on the pituitary gland. Intracerebroventricular administration of GnIH/RFRP further inhibits reproductive behaviors in songbirds and rodents, possibly via direct actions on the GnRH system. The expression of GnIH/RFRP is regulated by melatonin which is an internal indicator of day length in vertebrates. Stress stimuli also regulate the expression of GnIH/RFRP in songbirds and rodents. Accordingly, GnIH/RFRP may serve as a transducer of environmental information and social interactions into endogenous physiology and behavior of the animal. Recently, it was shown that GnIH/RFRP and its receptor are also expressed in the gonads of birds, rodents and primates. In sum, the existing data suggest that GnIH/RFRP is an important mediator of reproductive function acting at the level of the brain, pituitary, and the gonad in birds and mammals
Asymmetry, sex differences and age-related changes in the white matter in the healthy elderly: a tract-based study
<p>Abstract</p> <p>Background</p> <p>Hemispherical asymmetry, sex differences and age-related changes have been reported for the human brain. Meanwhile it was still unclear the presence of the asymmetry or sex differences in the human brain occurred whether as a normal development or as consequences of any pathological changes. The aim of this study was to investigate hemispherical asymmetry, sex differences and age-related changes by using a tract-based analysis in the nerve bundles.</p> <p>Methods</p> <p>40 healthy elderly subjects underwent magnetic resonance diffusion tensor imaging, and we calculated fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the major white matter bundles.</p> <p>Results</p> <p>We identified hemispherical asymmetry in the ADC values for the cingulate fasciculus in the total subject set and in males, and a sex difference in the FA values for the right uncinate fasciculus. For age-related changes, we demonstrated a significant increase in ADC values with advancing age in the right cingulum, left temporal white matter, and a significant decrease in FA values in the right superior longitudinal fasciculus.</p> <p>Conclusion</p> <p>In this study, we found hemispherical asymmetry, sex differences and age-related changes in particular regions of the white matter in the healthy elderly. Our results suggest considering these differences can be important in imaging studies.</p
A New Soil Model and Dynamic Soil Properties
A series of cyclic triaxial loading tests with varying strain amplitude were performed on samples of clay and sand. Three types of polynomial functions and a hyperbolic function were applied to express the experimental nonlinear hysteresis curve of soils under cyclic loading conditions. These functions were used for the earthquake response analysis of the actual ground containing alluvial clay layer and of the idealized saturated sandy soil ground whose stiffness gradually decreases as the development of pore-water pressure. The results of the dynamic responses and the liquefaction potential were compared for a particular actual site and an idealized site by using the presented models and the hyperbolic function model
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The NOTCH Pathway in Head and Neck Squamous Cell Carcinoma
Comprehensive genomic analyses have been performed for head and neck squamous cell carcinoma (HNSCC), revealing a significant rate of NOTCH1 mutations and identifying NOTCH1 as the second most frequently mutated gene after TP53. Most NOTCH1 mutations are considered inactivating, indicating that NOTCH1 is a tumor suppressor gene. On the other hand, cohorts from Asian populations with HNSCC have shown activating NOTCH1 mutations. HNSCC with NOTCH1 mutations have a worse prognosis than the NOTCH1 wild-type tumors. Additional data on other NOTCH family members have shown that NOTCH promotes HNSCC progression. NOTCH family members, including NOTCH pathway genes, are upregulated in HNSCC compared with normal tissues, and inhibition of the NOTCH pathway decreases cell proliferation and invasion. NOTCH activity in HNSCC is therefore contextual, and NOTCH in HNSCC is considered to have a bimodal role as a tumor suppressor and an oncogene. In this review, recent understandings of NOTCH pathway genes, including NOTCH genes, in HNSCC are described. In addition, the implications of NOTCH pathway alteration for HNSCC-specific NOTCH-targeted cancer therapy are explored
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